ExH has changed his mind about settlement - so confused right now

I have been trawling through various sites and just cannot seem to find an answer to this so would be really grateful if anyone can share their knowledge on this?

He left me years ago and since that time has made many promises about finances, constantly changing his mind and being generally very unreliable.

We have no money at all to speak of apart from around £50k equity in the house, we agreed between ourselves (I have an email to confirm) after a lot of conversations that I would stay in property until youngest is 18, then we would split equity 50/50. He pays minimum maintenance, and nothing towards the mortgage but arrangement suits me as I will never get another mortgage in my name so it means the children still live in family home, close to school and friends etc.

He has now split from the woman he left me for and is renting a flat in not a very nice area, so he now wants me to sell the house 5 years ahead of when we had planned and agreed, as he wants his money now. I cant afford to go to court over this.

My problem is that if I sell, I honestly dont know where we will live as I have a bad credit rating so noone will touch me with a bargepole! I have no friends or family that I could impose on either.

Does he have the right to force me to sell now, because his circumstances have changed? He is insisting he does, and is coming around tomorrow with an estate agent and I am so worried, just dont know what to do. He says it was only ever a goodwill gesture, and I cannot force him to stay on mortgage if I cannot buy him out (which I cant). I will try and get help on Monday but if anyone can help me in the meantime, that would be so great. Thank you